| 100% | MOTOR | 5 | Internal combustion engine |
| 91% | ETIENNE | 7 | Internal combustion engine inventor Lenoir |
| 82% | CARBON | 6 | Colourless, odourless, toxic gas produced by an internal combustion engine |
| 80% | DIESEL | 6 | Rudolf —, German engineer who invented a type of internal combustion engine |
| 76% | MAGNETO | 7 | Small electric generator such as that producing a spark in an internal combustion engine |
| 69% | HEMI | 4 | Kind of internal-combustion engine |
| 69% | VFOUR | 5 | Kind of internal-combustion engine |
| 67% | OTTO | 4 | Four-stroke internal-combustion engine inventor |
| 67% | VALVETRAIN | 10 | * Part of an internal-combustion engine |
| 67% | MAGNETOS | 8 | Alternators in some internal-combustion engines |
| 66% | ETIENNE | 7 | ___ Lenoir, inventor of the internal-combustion engine |
| 61% | GASENGINE | 9 | Internal combustion device |
| 61% | HEATENGINE | 10 | Internal combustion device |
| 61% | WANKEL | 6 | Felix —, German engineer; inventor of a four-stroke internal-combustion engine |
| 57% | HEMIS | 5 | Some combustion engines |
| 57% | ENGINE | 6 | Internal combustion __, developed in the 1800s |
| 55% | INTERNAL | 8 | __ combustion engine; invented by Étienne Lenoir |
| 55% | INJECTORS | 9 | Fuel sprayers in combustion engines |
| 55% | COMBUSTION | 10 | Internal engine process |
| 54% | BENZ | 4 | Karl —, German designer who built the first car to be driven by an internal-combustion engine |
| 54% | CHAMBERS | 8 | Combustion __; engine components that burn fuel |
| 52% | INTERNAL | 8 | An __ combustion engine powers a motor car |
| 51% | HEMI | 4 | Engine with dome-shaped combustion chambers |
| 49% | FUELINJECTION | 13 | Internal combustion process, and an explanation of the other long Across answers |
| 46% | PISTONENGINE | 12 | Internal-combustion device |
| 33% | REV | 3 | Accelerate an engine |
| 33% | RETRO | 5 | Certain rocket engine |
| 33% | RETRO | 5 | Small rocket engine |
| 33% | REV | 3 | Gun the engine |